By James Helm BBC News, Dublin

About 15,000 Nigerians are thought to live in the Irish Republic

Ireland's government has rejected an appeal for a deported Nigerian student to be allowed back into the country to complete his high school exams.

Olukunle Eluhanla, 19, was among more than 30 Nigerians deported last week after their asylum applications failed.

Opposition politicians have called for the student - apparently deported in his school uniform - to be allowed back to the Irish Republic from Nigeria.

But the Irish government said reversing the decision would set a bad precedent.

'Chaos' warning

The case of Mr Eluhanla, now in the Nigerian commercial capital, Lagos, has sparked widespread concern.

He has been pictured in Irish newspapers wearing his uniform from Palmerstown Community School in Dublin.

The teenager, who arrived in Dublin unaccompanied two years ago, says he has no family in Nigeria but that supporters in Ireland have arranged somewhere for him to stay.

However, Irish Justice Minister Michael McDowell rejected calls for Mr Eluhanla to be permitted to return to take his Leaving Certificate exams in June.

He said the case had been examined twice by independent bodies, whose findings had cast doubt on parts of the teenager's asylum claim.

Protest planned

Mr McDowell also warned that Ireland's asylum system would fall into chaos if the government granted automatic asylum to orphans.

The head of the Irish Refugee Council called the deportation "inexcusable".

Children and their mothers are said to be in hiding in the Irish town of Athlone because they face being deported back to Nigeria.

Last week's deportation also left some children in Ireland while their mothers were returned to Lagos.

Opponents of the policy, including some of the student's classmates, plan to protest outside the Irish parliament building on Wednesday.

Around 15,000 Nigerians are thought to be in Ireland, with most of them living in Dublin.

Ireland has only witnessed significant immigration relatively recently, following its economic success over the past decade.