JERUSALEM, Oct 4 (Reuters) - A pro-Palestinian Nobel peace laureate has lost an appeal in the Israeli Supreme Court against her deportation after describing Israel as an apartheid state engaged in ethnic cleansing.

Mairead Corrigan Maguire won the Nobel peace prize along with Betty Williams in 1976 for their efforts to end sectarian violence in their native Northern Ireland.

Maguire, who was banned from Israel for 10 years after trying to breach its naval blockade of the Hamas-run Gaza Strip in June, was detained and ordered deported last Tuesday after flying into Tel Aviv's Ben-Gurion airport.

She appealed the order in the Supreme Court, which according to a transcript of the hearing, voiced incredulity at her argument that she had been unaware of the ban.

I hope the court will allow me to stay in Israel with my Israeli and Palestinian friends, Maguire told reporters before the court turned her down on Monday.

There will be peace in this country, I believe it, but only when Israel ends apartheid and the ethnic cleansing of the Palestinian people, she said, using terminology Israel has long challenged. (Writing by Jeffrey Heller, Editing by Noah Barkin)