Two people who were believed to be in Queens Park, Invercargill, at the same time as missing man Raymond Horn on February 15 are being asked to come forward to speak to police.
The pair were believed to be in the Invercargill park about 2.20pm on the Monday afternoon Horn went missing.
A police statement issued last night said they knew Horn was in the park at the same time.
''We're hoping they might have seen Raymond and can help us continue to build a timeline of his movements.''
Last Monday, Horn, who has dementia, walks with a limp and is non-verbal, went missing from Walmsley House, a rest home in Richmond, Invercargill.
Teams of Land Search and Rescue volunteers, other volunteers and police have been searching for him since, to no avail.
Last Friday, police released CCTV footage which showed Horn on the corner of Yarrow and Mary streets about 9.30am, just after he left Walmsley House, and then walking along Yarrow St towards Queens Drive.
The last confirmed sighting of him was captured on CCTV at 2.10pm the same day, near the children's playground in Queens Park.
Anybody with information is asked to call police on 105 or Crimestoppers on 0800 555111 quoting file number 210215/8028.