New rules on the arrest and questioning of suspects have come into force amid concerns from solicitors about their impact.

The changes under the Criminal Justice Act will give everyone being held in police custody the right to speak to a solicitor, regardless of whether they are going to be interviewed.

Lawyers have raised concerns about the potential impact on workload, with bar associations across Scotland indicating they will boycott the new police station duty solicitor scheme.

The Scottish Legal Aid Board (SLAB), which is responsible for ensuring suspects have access to legal advice, said measures were in place to address the concerns of private solicitors.

The new rules will replace the separate concepts of arrest and detention with a single statutory power of arrest without warrant where there are reasonable grounds for suspecting a person has committed an offence.

Officers will be allowed to release a suspect with conditions for up to 28 days for further investigation, with the power to re-arrest them.

Police will be required to "take every precaution to ensure a person is not unnecessarily held in police custody" and the changes also allow for improved protections for under 18s.

The changes have been brought in as a result of the recommendations of Lord Carloway's 2011 review of Scottish criminal law.

Justice secretary Michael Matheson said they represented "some of the most significant changes to police procedures in Scotland for at least a generation".

Police Scotland assistant chief constable Wayne Mawson welcomed the act as offering a "better balance" between keeping people safe and protecting the rights of those suspected or accused of crime.

A spokesman for the Scottish Legal Aid Board said: "We understand the concerns some solicitors have about managing requests for advice in police stations alongside the other demands of running their businesses.

"There is no obligation on solicitors to respond to requests for advice from their own clients.

"Where they can't, support will be available through the duty scheme from our own employed solicitors on the Solicitor Contact Line and the PDSO (Public Defence Solicitors' Office), as well as the 581 private solicitors on the duty rota.

"If we have to use our employed solicitors more often because of pressures on local duty plans then it is likely that we will have to expand this service in those areas, and have taken steps to do so. This will help ensure that those in police custody and in need of advice are able to get it quickly."