Lighthouse Illawarra senior pastor Paul Bartlett had to set up about 300 extra chairs in his Wollongong church to cater for the masses of parishioners keen to hear from American XXXChurch pastor Craig Gross, who will attend Sexpo in Sydney this week.

The pastor has been delivering anti-pornography messages in the US for about 10 years by handing out bibles with covers proclaiming "Jesus loves porn stars" because he believes it is destructive to families and relationships.

"Some people would rather opt for pornography than real experiences with a loved one and I don't see that as an aid," he said.

"Also, in many cases the porn industry is very one-sided and it's about mainly what the male wants ... and in marriage, it doesn't really work that way because you have two people who have needs."

BLOG: Church takes porn message to the sinnners

He also said many Christian children, unable to talk to their parents about sex, ended up using internet porn as sex education.

"Pornography is fantasy, it's not real, but it has become sex ed and the average age someone sees [porn] now is 11," he said.

"It's destructive because we are setting people up to expect something of sex that doesn't match what they see in the movies."

Pastor Bartlett said his congregation in both Shellharbour and Wollongong had enthusiastically embraced their first "Porn Sunday".

"It's been really great - there were a few funny looks when I announced it a month ago but when I explained that it was about improving conversation about something churches never talk about, people were really excited," he said.

"We had some new faces and there was a lot of interest from mums and dads who have told me how shocked they were to catch their 10 or 11-year-old sons watching porn.

"They really didn't know what to do about that and porn is considered so taboo, which is why this is exactly what we should be talking about at church."