Officers said they are trying to track down a man they believe is involved in the incident.
A spokesman for Newport Police said: "Reports were received of attempted thefts in Vineyard Road, Victoria Park and Ten Bank in the early hours of Thursday and Friday, May 12 and 13.
"Car keys were stolen from properties but no cars were reported stolen.
"Officers would like to identify a man believed to be involved.
"He is described as white, slim and around six-foot tall.
"He was seen wearing a black face covering and dark clothing.
"Officers would like to hear from anyone who may have seen him in and around Vineyard Road, Victoria Park or Tan Bank or may have captured him on CCTV or dash cam."
Anyone with information can report it using www.westmercia.police.uk/tua/tell-us-about/cor/tell-us-about-existing-case-report/ quoting reference 22/47031/22.