The Scottish Government has been accused of bias over its choice of speakers for the International Policing Summit, taking place on Monday.
The event will see delegates from Denmark, Finland, Ireland, Luxembourg, Netherlands, Northern Ireland and Norway talk about their experiences of police reform.
Justice Secretary Kenny MacAskill will also speak at the event.
However Cosla, the umbrella body representing local authorities, said the speakers had been selected to fit the option of introducing a single police force in Scotland.
The criticism follows Cosla's own event on policing last week during which senior police officers and local government officials discussed the Government's reform proposals.
The SNP administration is said to be pushing ahead with the move to create a single force despite high-profile complaints from serving officers and local authorities.
Cosla president Pat Watters said: "Our event was designed to be balanced by inviting participants who were both in favour of and opposed to the single-force model - we felt it imperative that we listened to the whole range of views.
"When the Cabinet Secretary and the government snubbed our offers of speaking opportunities, they went further in not even sending a civil servant along to listen."
Mr Watters added: "At their event, in the Government's own words, 'We will hear from a variety of countries with national police services ... so we can understand how this might work in Scotland'.
"Two things occur to me in relation to this. Firstly, shouldn't we know it would work in Scotland before we make the decision?
"Secondly, why is the Government unwilling to listen to any examples from abroad of strong regional policing?"
The idea of a single force was outlined in a government proposal on the future of the police in January and a consultation started in February.
Other options included having fewer forces or a more streamlined version of the existing system.
Scottish Liberal Democrat leader Willie Rennie said the party's justice spokeswoman, Alison McInnes, would attend the conference.
He said: "We are keen to hold the SNP government to account every step of the way and we seek to persuade them to reject a single force.
"We are disappointed there is no expert opinion in opposition to a single force like at the Cosla conference, which was balanced. This is the SNP Government in full bulldozer mode rejecting all opinion that they disagree with."
A Scottish Government spokesman said: "This government has consulted widely and engaged regularly with police, local authorities and all other interested parties on the best way forward for reform, and we will continue to do so.
"Hearing from experts in other countries is an important part of this process and exactly the sort of considered, open debate we should be having.
"Strong, local democratic accountability will be at the heart of new police services in Scotland."