By James Rodgers BBC correspondent in Gaza

For the Palestinians of the Gaza Strip, labouring jobs in Israel have long been a major source of income.

With the extra security measures introduced during the Palestinian intifada, or uprising, that source of income has been drastically reduced.

And now some 20% of those workers who do have permits are choosing not to use them, saying that the conditions in Israel have become intolerable.

Some leave home before midnight to reach work on time

Two years ago, 125,000 people from Gaza held permits to work in Israel, according to the Palestinian Labour Ministry.

When the intifada or uprising began, that number dropped to zero.

Fearing attacks from militant groups, the Israelis sealed off the Gaza Strip.

Long working day

Now permits are once again being issued, though in much smaller numbers.

The figure currently stands at more than 12,000, Palestinian officials say.

The threat of suicide bombers means curbs are unlikely to be lifted

But only about 10,000 workers are actually using them on a daily basis.

Those who choose to stay in Gaza say they are doing so because security measures and harassment have made their lives intolerable.

Because of stricter checks and lengthy journeys, some workers have to leave their homes before midnight for a working day which begins at six or seven the next morning.

They are passing up daily wages worth about $50.

This in a territory where the United Nations estimates that some 60% of the population now survives on $2 a day or less.

Extra employment in Israel would bring much needed funds into the Gaza Strip's economy.

The Israelis say they want to increase the number of permits to 14,000.

While the threat of suicide bombers remains however, there is little prospect of security measures being relaxed.