A West Australian community services organisation says it is disappointed the Liberal Party has declined to participate in a roundtable discussion about homelessness later this month.

Ruah Community Services will host the discussion in Perth on June 15 in conjunction with sector providers St Bartholemew's House and Foundation Housing.

The organisation had sent out invites to the Liberal Party, WA Labor, and the Greens, as well as various community leaders.

Labor's candidate for Perth Tim Hammond has agreed to attend the event, as has Greens Senator Rachel Siewert.

But despite trying to secure a Liberal Party representative for almost a month, none has been forthcoming.

Ruah's CEO Debra Zanella said that was surprising.

"It is disappointing. We're particularly passionate about this subject," she said.

"I think it's an opportunity for the parties to come and tell us what their thinking is, and where their policy planning on this issue is.

"But it's also an opportunity for us to have robust and good dialogue about where we need to head in this space."

Federal MPs declined invitation

The organisation said it first reached out to Social Services Minister Christian Porter early in May, but he declined the invitation on May 24.

Ms Zanella said calls were then made to Senator Michaelia Cash, Member for Swan Steve Irons, Hasluck MP Ken Wyatt, and the Liberal candidate for Perth Jeremy Quinn, all of whom declined.

Earlier this week Ruah received a letter from WA Liberal state director Andrew Cox, which said the party would not be providing a representative for the discussion.

However, Mr Cox did provide a statement to be read out during the forum, outlining the party's commitments to addressing homelessness.

Ms Zanella said the letter did not offer a reason for the decision.

"It's hard not to infer from that — and I am sure this is not the case — that they don't see this as an important agenda item. But it is difficult to understand," she said.

The ABC has contacted Mr Cox for comment.