LONDON (Reuters) - About a fifth of the world’s Anglican leaders are boycotting a meeting this week in protest at the U.S. Episcopal Church’s ordination of gay bishops and blessing of same-sex couples, organizers said on Tuesday.

Their refusal to attend the conference of primates in the Irish capital Dublin underlines tensions which are threatening split the loose group of churches that make up the 80-million strong worldwide Anglican Communion.

The Anglican Communion said the seven primates, or leaders, who had not turned up in protest at the stance taken by the U.S. Episcopal Church had nevertheless “reiterated their commitment to the Communion and to the Archbishop of Canterbury.”

Canon Chris Sugden, of the group Fellowship of Confessing Anglicans, wrote in “Evangelicals Now” magazine that the leaders’ absence “calls into question the ability of the Archbishop of Canterbury (Rowan Williams) to fulfill his role as gatherer of the Communion.”

Conservatives want sanctions imposed on the U.S. church, headed by Presiding Bishop Katharine Jefferts Schori.

They object to her presence at the meeting, and are angry at her church’s recent ordination of a lesbian bishop despite a request not to do so issued by the Communion after its first gay bishop, Gene Robinson, was installed in 2003. Conservative churches say pro-homosexual reforms are unbiblical.

Thirty-eight primates of the autonomous provinces were invited to the gathering, held every two years. However, the Communion said only 24 would attend in Dublin, with others unable to come because of ill-health or other commitments.

Sugden had earlier told Reuters that he expected 10 would stay away. “There are only so many times you can appeal to people to turn up and make their voice heard,” Sugden wrote.

Conservative primates say they are disillusioned by a lack of disciplinary action against the U.S. church, despite recommendations made at previous primates’ meetings, and add that there had been a lack of consultation before the meeting.

The Anglican Communion said primates refusing to attend included those of the Indian Ocean, Jerusalem and the Middle East, Nigeria, South East Asia, the Southern Cone of Latin America, Uganda, and West Africa.

Last June, Schori said that plans to discipline her church violated Anglican traditions, moving toward a centralized authority.

Conservative churches rejected last November a proposed landmark agreement, called a covenant, designed to prevent splits in the Communion on issues such as gay bishops and same-sex unions, which had been supported by Williams.