NSW Catholics urged to oppose gay marriage

Catholic Archbishop Anthony Fisher says married couples must resist being bullied into redefining marriage.

Catholics should respect and love all without accepting gay marriage, the archbishop told a packed congregation at St Mary's Cathedral in Sydney.

More than 120 couples joined the mass on Sunday morning to renew their wedding vows and celebrate more than 1700 years of marriage between them.

"Marriage brings together...man and woman, sex and love, love and babies, parents and children," the archbishop said in his homily.

"To say this is not to criticise anyone."

Archbishop Fisher said the faithful were often labelled as bigoted, with political and cultural forces trying to "bully us all" into redefining marriage.

"To say marriage is special is not to demean these other realities, rather it respects the diverse ways of being human and loving, not pretending away the differences," he said before couples renewed their vows.

Joan and Keith Dunsmore, who will celebrate their 65th anniversary, were among those who stood and promised to love and honour each other for the rest of their lives.

"It's a lovely feeling to renew our vows in this atmosphere," Mrs Dunsmore said after the mass.

She advised other couples to "talk it out" and work through problems together.