By David Ornstein

With his place under threat Strauss made his first Test ton since 2006

Centuries from Andrew Strauss and Ian Bell helped England build a huge lead and close in on a series victory on day three of the third Test in Napier.

Strauss, whose position had been under serious threat, hit an unbeaten 173 against New Zealand and put on 187 for the fourth wicket with Bell (110).

It was Strauss's highest Test score as he and Tim Ambrose guided England to 416-5 at the close, a lead of 501.

New Zealand will need to chase down a world record score to beat England.

Interview: England's Andrew Strauss

Ryan Sidebottom's 7-47 on day two laid the foundations, while Strauss and Bell have put England, who resumed on 91-2 with an overnight lead of 176, in overwhelming command.

Strauss had not hit a century since his 128 against Pakistan in July 2006 and this knock easily surpassed his previous Test best of 147 against South Africa in January 2005.

Although it was by no means the 31-year-old's most glittering innings, it was arguably his most important.

606: DEBATE The critics were beginning to round on Strauss with increasing venom David O, BBC Sport

Strauss, who is centrally contracted, was dropped before the 2007 tour to Sri Lanka tour and it had been suggested that failure to score a century in Napier could mark another period in the international wilderness.

But with glorious sunshine overhead and a hard, flat pitch under foot, he profited from perfect batting conditions.

Despite the meagre first innings totals posted by both sides, the McLean Park wicket has been conducive to high run-scoring throughout, offering precious little to the bowling team.

England illustrated as much in the morning session, Kevin Pietersen pulling Chris Martin for six in the third over and Strauss driving Tim Southee for four in the fourth.

The pair appeared to be cruising along until captain Daniel Vettori, who hitherto had taken only three wickets in the series, brought himself into the attack and struck in his third over.

Bell hooks Martin for four to bring up his seventh Test ton

Pietersen had started to open up with increasing success but, two balls after coming down the track to loft Vettori for four, he fell to an outstanding catch by Ross Taylor at slip.

The dismissal failed to halt England's progress, however, and Bell was quickly into his stride with two fours off Jeetan Patel through the covers and a six off Vettori over long-on.

England batted confidently to the lunch break, which they reached on 167-3, but Strauss and Bell really started to press home their advantage after the interval, scoring 135 runs in the middle session alone.

With the new ball still 19 overs away at the start of the second session, New Zealand had little choice other than to bowl spinners Vettori and Patel, which enabled England to cut loose.

In the 66th over Bell swatted Patel for four with a sumptuous cover drive and then flicked him over mid-wicket for six the next ball.

Bell's cut off Vettori flew fortuitously over slip to bring up his 50 and he swiftly became the second youngest England batsman to reach 2,500 Test runs with a display of dazzling strokemaking.

New Zealand took the new ball just as Strauss closed in on three figures, and he duly played and missed at three deliveries from Martin before driving Vettori through the covers for four, prompting a euphoric celebration.

Vettori captured all three England wickets on day three with 3-135

While the significance of Strauss's ton should not be underestimated, Bell's was by some distance the more eye-catching.

The 25-year-old was without a century in his previous 23 innings but he played with style and panache to bring up his century.

He was finally caught by Mathew Sinclair at mid-off as he attempted to lift Vettori down the ground.

Paul Collingwood edged the New Zealand skipper for four and then slog-swept him for a huge six in the 101st over.

But England's one-day captain looked a little uncomfortable in his short innings and it hardly came as a surprise when Vettori had him caught and bowled for 22.

The home skipper battled away to return figures of 3-135.

New Zealand could have made further inroads when Taylor dropped Ambrose, who also narrowly survived an attempted run-out, off the bowling of Patel.

But the day belonged to one man and one team. England are now firmly on course for a victory that would ensure their first overseas series win since January 2005.